The invention relates to the synthesis of halichondrin B and norhalichondrin B.
Halichondrins are a class of polyether macrolides isolated originally from the marine sponge Halichondria okadai Kadota. Halichondrins, especially halichondrin B and homohalichondrin B, exhibit an extraordinary in vitro and in vivo antitumor activity. However, the very limited supply of halichondrins from natural sources has prevented the full evaluation of thief potential clinical applications.